title: Recovery of megakaryocytopoiesis in vitro in children with acute lymphoblastic leukemia during induction of remission.
abstract: In children with acute lymphoblastic leukemia (ALL), megakaryocytopoiesis was investigated in vitro by the semisolid agar culture technique. In untreated ALL the median number of committed megakaryocyte progenitor cells (CFU-Mk) in the bone marrow was 2 (range less than 0.1-8) per 10(5) bone marrow cells instead of 30 (range 14-93) in controls, the impairment being dependent on the degree of leukemic bone marrow infiltration. However, if the number of CFU-Mk was related to residual nonleukemic bone marrow cells only, two-thirds of the children investigated had a frequency of CFU-Mk within the normal range. After 2 weeks of induction therapy the majority of the children had a low number of CFU-Mk in the bone marrow (median 6, range 0.5-40), a fact that could no longer be explained by a dilution of CFU-Mk by leukemic cells. After 4 weeks of chemotherapy (day 29) the frequency of CFU-Mk had risen to 18 (range 3-67) per 10(5) bone marrow cells, a value still significantly (p less than 0.01) below the normal range. In contrast to the changes in the number of CFU-Mk the median cell number per megakaryocyte colony remained constant during induction of remission. After cessation of long-term chemotherapy all children investigated had a normal number of CFU-Mk, suggesting that no permanent chemotherapy-related damage to committed megakaryocyte progenitor cells was induced.
authors.affiliation: Department of Pediatrics (Inselspital), University of Berne, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Hirt
authors.forename: A M
authors.initials: AM
authors.lastname: Schmid
authors.forename: A R
authors.initials: AR
authors.lastname: Luethy
authors.forename: E
authors.initials: E
authors.lastname: Gugler
authors.forename: H P
authors.initials: HP
authors.lastname: Wagner
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D007223:Infant; D007231:Infant, Newborn; D008533:Megakaryocytes / Q000502:physiology*; D010976:Platelet Count; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000097:blood* / Q000188:drug therapy; D012074:Remission Induction